-5.74% is the change from 871 to 821
Calculation steps:
[( 821 - 871 ) ÷ 871] x 100 = -5.74%
Formula
Percentage change = [(821 - 871) / 871] x 100
Subtract the new number by the original number
821 - 871 = -50
-50 ÷ 871 = -0.0574052812858783
-0.0574052812858783 x 100 = -5.74%